Over centuries and millennia, this process can fragment even dense cortical bone into particles too small to recognize as human.

Permafrost — permanently frozen ground — provides a very different preservation environment.

When biological material is buried in genuine permafrost and remains frozen, it can be preserved in extraordinary condition: the woolly mammoths that emerge from Siberian permafrost with their flesh, hair, and stomach contents intact are the most dramatic examples of what permafrost preservation can achieve.

Alaska has permafrost, and some Alaskan specimens benefit from permafrost preservation.

But permafrost is not uniformly distributed, not uniformly stable, and not uniformly favorable for preservation.